Board members of the Metropolitan Water District created a “secret cabal” to shift expenses to local residents, the San Diego County Water Authority said in court papers ahead of a Thursday hearing in San Francisco.

Timeline of litigation

June 2010 -- The governing board of the County Water Authority voted unanimously to sue Metropolitan Water District, it’s largest supplier, so it will reduce the rate it charges for delivering water.

May 2011 -- Board members for Metropolitan consider removing financial incentives for customers in San Diego County in response to the lawsuit and delay a decision.

June 2011 -- Metropolitan cuts funding for conservation and supply programs in San Diego County over the legal spat, but leaves some rebates for homeowners intact.

Aug. 2011 -- The water authority files court papers signaling its desire to expand the legal case to include items not in the initial lawsuit. The formal request is expected Friday.

The lawsuit is part of a feud between local water officials and their largest supplier over how much Metropolitan charges. The Los Angeles-based agency is run by a 37-member regional board that has left the four local representatives feeling disadvantaged over water rates, supplies, expenses and other issues.

“The majority members of Metropolitan’s Board have consistently acted only in their own narrow individual interests and ... have regularly conducted secret meeting outside of regular Board meetings where they have entered into agreements to set rates and established other practices expressly designed to shift costs to the Water Authority,” said a court brief by San Francisco lawyer John Keker, who represents the water authority.

Water authority lawyers today will formally ask Superior Court Judge Richard Kramer for permission to expand their water-pricing lawsuit against the Los Angeles-based water supplier so that it includes alleged breaches of contract and “fiduciary duty.”

Kramer isn’t expected to decide on the scope of the case until late October and a ruling on the merits isn’t likely for months. But water authority officials said on Thursday that Kramer allowed the Imperial Irrigation District and the San Diego-based Utility Consumers’ Action Network to remain part of the proceedings despite Metropolitan’s opposition.

“It’s a very good sign,” said Dennis Cushman, assistant general manager for the county water authority. “It’s obvious that Judge Kramer … wants to hear more voices on the issues.”

Beyond the specifics of the lawsuit, the unrest is fueled by rapidly escalating water rates across the region. Agencies at every level are under pressure by consumers to control costs after residential bills have jumped by 60 percent or more in recent years.

Local officials pin some of the blame on Metropolitan, the largest wholesale water provider in the region, which in turn says the increases have been driven by attempts to spread fixed costs over smaller amounts of water sold during the recent drought and recession.

A Metropolitan spokesman said Thursday that the agency was withholding comment, but in court papers it has steadfastly maintained that its billing practices are fair. Agency lawyers have said that the law gives them lots of leeway to set rates, and that the agency “has at all times acted well within the confines of this discretion.”